PCBs left behind in the Hudson River after a cleanup project by General Electric Co. have spread to contaminate nearby areas that were dredged, according to a consultant hired by the environmental group Scenic Hudson.

The study found elevated PCB levels in dozens of areas where the chemical was dredged from the river bottom and then covered with clean fill during the massive Superfund cleanup.

Study author Remy Hennet said, "The only reasonable conclusion is that the dredged areas have been recontaminated by PCB-laden sediment from non-dredged areas located nearby."

The study also found some PCB "hotspots" in the river, including near Mechanicville and Schuylerville in Saratoga County.

GE dredged PCBs from about 40 miles of river bottom between Fort Edward and Troy between 2009 and 2014. That amounted to about 310,000 pounds, or 72 percent of what is now known to be in the river. That means about 120,000 pounds still remain along the bottom, including in the navigation channel of the state-owned Champlain Canal.

Hennet's work was based on 1,800 river sediment samples collected between Troy and Fort Edward by the state Department of Environmental Conservation in 2017. DEC took the samples at a cost of $2 million after federal officials declined to do so.

Hennet is the owner of S.S. Papadopulos and Associates Inc., a water and environmental engineering firm, and has more than two decades of experience in studying environmental pollution.

GE spokesman Mark Behan disputed the findings. "Our analysis is starkly at odds with these claims," he said.

Behan said that the state samples show that PCB sediment levels in the river after dredging "declined as much as 92 percent ... Where PCBs were detected in river sediments, 99.8 percent of the samples showed PCB concentrations below the level at which EPA said dredging was warranted.

"The Hudson River dredging project is working as the U.S. Environmental Protection Agency and New York state projected," Behan added.

Hennet's report comes as the U.S. Environmental Protection Agency, which oversaw GE's work on the $1.7 billion project, is considering whether to certify that the work satisfies a 2002 cleanup agreement between GE and EPA.

Should EPA issue that certification, GE would also be released from future environmental liability, something that DEC, Scenic Hudson and other environmental groups oppose as they argue the cleanup is not done.

"It would be outrageous if the EPA ignored these findings and issued General Electric a certificate of completion, effectively closing the door on further cleanup of the Upper Hudson," said Scenic Hudson President Ned Sullivan.

Scenic Hudson, along with other environmental groups and DEC, believe that PCB levels in the river remain too high, and want EPA to require GE to expand the cleanup, as well as study the lower Hudson River south of Albany.

This is not the first time that Hennet has faulted the effectiveness of the cleanup. Last year, he called EPA data on declining PCB levels in river fish "uncertain," "unreliable" and "deceptive."

"It would be reckless for EPA to issue a certificate of completion for the Hudson River dredging project without the data and the science to prove this cleanup protects public health and the environment," said DEC Commissioner Basil Seggos.

He said the state tests show "the cleanup of the Hudson River is not complete. DEC will continue to use all legal tools at our disposal to ensure EPA does not let GE off the hook and betray both the river and the communities that depend on it."

"EPA is still intensely engaged with our state partners, including the review of surface sediment data collected in 2017," said EPA spokeswoman Larisa Romanowski. "Our shared goal is to have a comprehensive and exhaustive understanding of the data and develop joint findings and conclusions in the near future. It is important to the public and communities throughout the Hudson Valley that EPA and DEC collaborate as agencies and give this the attention it deserves."

In February, DEC and two federal agencies reported that the PCB levels in the river as recently as 2014 remained well above federal safety guidelines, as well as above state standards meant to protect humans and animals that eat river fish, and likely will remain high for decades to come.

The U.S. Fish and Wildlife Service and the National Oceanic and Atmospheric Administration also issued the February report.

The joint federal/state report relied on more than 10,000 tests of the river — including sections of the river south of Albany, which was not dredged — taken between 1976 and 2014. More than 95 percent of those samples were for the dredged portion of the Hudson.

About 85 percent of samples exceeded standards for fish and other aquatic life; more than half exceeded the standards for safe human consumption of fish. Drinking water safety standards were exceeded in about 5 percent of the samples.